Rotatable carbonizing machine



Dec. 14, 1954 5 Sheets-Sheet 1 Filed Feb. 11, 1952 DeC- y14, 1954 F. E. PINDEXTER ET A1. 2,597,068

ROTATABLE cARBoNrzING MACHINE Filed Feb. ll, 1952 5 Sheets-'Sheel'l 2 FIG2.

Deu 14, 1954 F. E. PolNDl-:XTER ET A1. 2,597,063

ROTATABLE CRBONIZING MACHINE 5 Shee'ts-Sheet I5 Filed Feb. 1l, 1952 FIGI 2.

DeC- 14, 1954 11E. Po|NDExTER ET AL 2,697,068

ROTATABLE CARBONIZING MACHINE y Filed Feb. 11, 1952 5 sheets-sheet 4 wwf/146% DeC- 14, l954 F. E. PolNDExTER Erm. 2,697,068

ROTATABLE cARBoNrzING MACHINE Filed Feb. l1, 1952 y 5 Sheets-Sheet 5 Flew.

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United States Patent ROTATABLE CARBONIZING MACHINE Franklin E. Poindexter, Richmond Heights, and Frank W. Lowe, St. Louis County, Mo.

.Application February 11, 1952, Serial No. 271,058

6 Claims. (Cl. 202-106) This invention relates .to a machine for the rapid in troduction of heat into materials that are poor conductors of heat and especially for the carbonization of carbonaceous materials such as coal; and is more particularly directed to a retort device for increasing the rate of carbonization, the purity of distillation products, and reduction of heat required to carbonize a given quantity of material.

The primary object of the rinvention is to provide a machine for carbonizing coal that will utilize a higher percentage of the heat generated and will also materially decrease the time required to carbonize a given ramount of coal or other material.

Another object of the invention is to provide an improved stirring mechanism for the coal or other material being carbonized.

A further object of the invention is to provide an improved mechanism for recovering heat produced for distillation purposes and for separating some of the products distilled from the coal. K

Another object of the invention is to provide mechanism for preventing the collection or accumulation of distillation products on partsv of the. control mechanism in the retort.

Still a further object of the invention is to provide mechanism for recovering steam produced in the cooling4 of the char and using same to heat the retort portion of the device.

The invention consists in the provision of a retort of the cylindrical type which is rotatable in a refractory housing, the 4retorthaving an 'agitating or stirring device therein, including means heated to a point equal to or higher than the temperature of the retort for preventing condensation of products distilled from the coal and for scraping the interior of the retort.

The invention also consists in the provision of means for recovering the heat present in the char, converting itinto. steam, and introducing it into the retort after reheating with the heat derived from the space about the retort cylinder.

The invention further consists in withdrawing the gaseousffsubstance from the char before cooling, passing the gaseous material through a cooling device and thereafter washing the material forv removing oil from the gas and then reheating they fuel preparatory to burning for heatingv the char in the retort.

'Tn the drawings:

Fig. 1 is a somewhat schematic elevational view of a device embodying the invention,

Fig. 2 is. an enlarged elevational view of the retort,

Fig. 3 isa view of one end of the retort,

Fig. 4 is a view of the other end of the retort,

Fig. 5 isl a sectional view of a part of the retort,

Fig. 6 is a schematic view of they condensing. and washgi'g device usedin connection with the mechanism of- Fig. 7 is an enlargedv detail' view of the retort stirring mechanism,

Fig. 8 is a sectional view of a modified retort. mechanism,

Fig. 9 is an end view of the device shown in Fig. 8,

Fig. 10 is an end view of a modication of the invention, parts being removed to show detail,

Fig. 11 is a sectional view taken substantially along the line 11-11 of Fig. 10,

Fig. 12 is a sectional view taken substantially along the line 12-12 of Fig. 10,

y Y 2,697,668 Patented Dec. 14, 1954 rice Fig. 13 is a view of the other end of the device shown in Fig. 10,

Fig. 14 is a sectional view taken substantially along the line 14-14 of Fig. 13,

Fig. 15 is a side elevational view, partly in section, of a portion of a modified retort; and

Fig. 16 is an end View of the structure shown in Fig. 15.

The invention is embodied in the mechanism illustrated in the several views of the drawings in which the numeral 1 designates a retort made up of a cylindrical tubular member, the retort being closed at its ends by castings 2 and 3 and heated by suitable gas burners 4, 5 and 6. The material to be carbonized is fed into the retort 1 from hopper 7 by means of a screw conveyor 8 driven by a variable speed motor (not shown), and is subjected to a rapid stirring action by means of blades 9 attached to a shaft 1i) driven by motor 1l through chain l2. The blades 9 are disposed circumferentially about the shaft ii) so that the material within the retort is subjected to the repeated action of each of the blades.

As shown in Fig. l, the shaft l0 is led through castings 2 and 3 in eccentric collars 13 (Fig. 7) held in place by a plurality of set-screws 14. The eccentric collars act as bearings for the stirring or agitating device and provide means for adjusting the position of the blades on shaft 1) relative to the retort l. The shaft lib is hollow and contains an electric heating element l5, the purpose of which is to maintain the temperature or the shaft a few degrees higher than that of the interior of the retort, thereby preventing condensation of tars and other vapors on the shaft 10 as well as accumulation of dust and gritty material thereon.

The tube 16, shown in Figs. 1 and 2, serves as a support for thermocouple tubes 17, 18 and 19. The thermocouple tube 16, shown in Fig. l, supports a regulator 2li which controls the gas pressure within the retort. The regulator controls the speed of the exhaust fan 2l located in the outlet of the retort 1. The thermocouple 17 is shown connected to the gas regulator for the burner 4. In like manner, the thermocouples 18 and 19 regulate the flow of fuel to burners 5 and 6, respectively. The thermocouple shoes 22 (Fig. 5) are in contact with the inside wall of the retort and it is possible to automatically maintain a constant predetermined temperature in the three heating regions of the retort as determined by the gas burners 4, 5 and 6.

The char produced in the retort 1 is discharged into the feed screw or twist conveyor 23 driven by means of a variable speed motor 24. The portion of the screw disposed below the retort is tapered so that an approximately level surface of char remains above the screw at all times. The speed of the screw is regulated so that there is a layer of char above the screw at all times, the height of this char being determined by a tester 25 shown in Figs. 2 and 3. The gases produced during carbonization in the retort are drawn through the char above screw 23 and escape at the take-off 26. The gases then pass to the dust box 27, to the condenser 28, and thence through washer 29. By means of the fan 2l the gases are forced into a storage reservoir (not shown). The reason for drawing the gases through the char is to filter the dust therefrom because it becomes troublesome if allowed to remain in the gases. The condensing system is shownin greater detail in Fig. 6, having a condenser 28 therein of a constant temperature reflux type. The gases derived from the dust box 27 are drawn through the condensing system by the pressure regulated fan 21 which removes the non-condensible gas from the washer 29 shown in Figs. 2 and 6.

The condenser 28 is filled with a liquid 30, the boiling point of which is somewhat lower than that of the heavy tar vapors in the gases. As these tars condense and pass through trap 33, the temperature of liquid 30 is raised to its boiling point and continues to boil at this temperature. The vapors of the liquid Sti are condensed in condenser 3l and cooled by means of cold water in a jacket 3.2. A pluralityl of these constant temperature condensers, using liquid of lower boiling points than liquid 30, may be introduced between the dust box 27 and the cold water condenser 35, in order to breakv up and separate the tars passing the condenser 28. This 3 constitutes means for separating the lighter and brighter tars as condensation progresses. Additional reflux condensers can be introduced at point 34 in the gas conduit. The last condenser in this conduit is a boiling water condenser which passes practically all of the water vapor in the gases along with the lighter oils that condense at temperatures below 100 C. These lighter oils and water are condensed in the cold water condenser 35.

A gas washer is introduced between the condenser 35 and the fan 21. In the system disclosed, the washer comprises a spray 36 discharging water that flows over pieces of petroleum coke 37. The lighter oils rise to the top of the wash liquid and are removed from a trap 38, the heavier liquid flowing out at the orifice 39.

The screw or twist 23 which carries hot char from the end of the retort discharges it into a steam box 40. This screw 23 actuates a stirrer 41 that agitates the char received from the screw. Water is sprayed onto the hot char by means of spray 42, thereby cooling the char and forming steam. The quantity of steam is controlled by the amount of water admitted, sufcient water being supplied to cool the char to the desired temperature. A pressure gauge 43 and a safety valve 44 are provided in the system.

Steam generated in the box 40 flows through the char being moved by screw 23, escapes through the gas takeolf 26, and becomes part of the gases moving through the condensing system. This steam serves two purposes, viz: it purges the char of gases and prevents the intake of air from the atmosphere since pressure in the condensing system is maintained below that of the atmosphere by fan 21 so that the gas from the retort 1 will flow to the condensing system'through the char in its path to the take-oit 26.

The surplus steam from steam box 40 is removed through the steam line 45, passes through the heat exchanger 46, and thence to the interior of the retort at port 47, thus recovering some of the heat of the waste gases from the burners 4, and 6 used to heat the retort. It also aids in the removal of the volatile matter in the material being carbonized by lowering the partial pressure of gases being removed in the carbonization process.

The steam box has a screw 48 rotatably mounted therein that removes the partially cooled char therefrom and discharges it into a suitable storage pit; or may 'direct it to a briquetting press (not shown).

The re box 49 encloses the heated portion of the retort 1 and is made up of a suitable refractory, thus maintaining the heat about the retort. The heat produced bv the burners is conned to the heating space Si) surrounding the retort. The depth of the space 50 varies in accordance with the heat requirements of the retort since the radiated heat through the retort is in proportion to the volume of the fire space surrounding it. The gas burners 4. 5 and 6 supply heat to the space 50 through orifices 51. The gas for the burners is derived from the storage reservoir supplied from the conduit 52 in which fan 21 is connected. The ,gas delivered to the burners passes through the heat exchanger 46 to which heat is supplied bv waste gases derived from the space 50 through orifices 53 and conduit 54. The gas passes from the heat exchanger 46 to a fan S5. thence to the mixing Valve 56, and then through a flexible conduit 57 to the burner manifold 58. Air is drawn through the heat exchanger 46 by a fan 59 and discharged into the mixing valve 56. The heated mixed gas and air passes through the manifold 58 to control boxes 60, 61 and 62 which regulate the flow of gas and air to the burners, thereby holding the temperature of the retort constant. These control boxes are actuated by thermocouples attached to the thermocouple tubes 17, 18 and 19 shown at 63, 64 and 65 respectively. A suitable shoe for the thermocouples is in contact with the inner wall of the retort and shown at 22. The carbonizing temperature within the retort 1 is automatically maintained at a predetermined value. Three thermocouples are used for the purpose of insuring against local over-heating and to secure a proper temperature gradient Within the retort.

The retort 1 is supported for rotation by a plurality of rollers 66 and 67, there being one on each side of the retort. These rollers engage an annular track 68, the supporting faces of which are at an angle of 90 with respect to each other. Axial movement of retort 1 with respect to track 68 is prevented by means of cleats 6.9 secured to the retort. Rollers 66 are secured to shaft 70 and held between brackets 71. The motor 11 drives shaft 70 and rollers 66, thereby rotating retort 1 by reason of the friction between the rollers and the track. Rollers 72 and 73 support the other end of the retort and roll on a fiat top annular track 74, its face of contact being larger than the width of the annular track which permits retort 1 to contract and expand, when cooled or heated, relative to the supporting frame or platform 76. The construction of track 68 and rollers 66 and 67 is such that they act as thrust bearings for preventing the retort drifting to the right or to the left. Wear of track 68 and rollers 66 and 67 may, in some cases, be excessive and, therefore, the flat top track is preferable. Track 74 is held between cleats 75 similar in construction to cleats 69.

Rollers 66, 67, 72 and 73 roll freely on anti-friction bearings mounted on shafts 70, 77, 78 and 79. Shafts 70 and 77 pass through bearings 80 and 81 and support casting 2. These bearings are adjustable in a horizontal direction by means of screws 82 and 83, the screws bearing against bearing blocks 84, thereby alfording a very accurate adjustment for positioning casting 2 relative to the retort. Casting 3 is similarly supported and adjusted on shafts 78 and 79 by screws 85.

Fig. l shows a partial view of castings 2 and 3, casting 2 tting into the front end of the retort and casting 3 f1tting over the other end thereof and sealed against gas leakage by packing rings 85 and 86. The rapid stirring of the material to be carbonized is essential because the heat penetration of the material, such as a ground coal, is proportional to the square root of the time of heat ow. The stirrer in the retort is carried by shaft 10 and consists of blades 9 secured to the shaft by means of hubs 87 and spokes 88 at suitable distances along the shaft 10. The blades are curved and set at an angle relative to the spokes 88 such that the material being stirred is lifted from the surface of the retort and scattered, the stirrer revolving opposite to the direction of rotation of the retort. Shaft 10 is driven by motor 11 by means of a chain 12 and suitable sprockets 89.

The heating element 15 within the shaft 10 is connected to a suitable source of power 92 through slip rings 91, collecting shoes engaging the rings 91 for attachment to lead wires. A generator 93 is provided in the circuit for supplying current to the shaft heating element 15, which maintains the shaft at a higher temperature than the carbonizing temperature of the material passing through the retort 1.

In a modied construction, a drying or pre-heating tube 94 is provided for certain materials, as shown in Fig. 8. A casting or fitting 95 is provided in place of casting 2, and a duplicate thereof is installed at one end of the tube 94. The casting 95 is supported by shafts 96 and 97 (Fig. 9) mounted on auxiliary supporting brackets 96' and 97, and movable with adjusting blocks 98 and 99. The shaft 96 is keyed to rollers 66 and to additional rollers (not shown) in supporting engagement with a second annular track 100. Thus the driving of the pre-heating tube 94 by motor 11 will transmit power to rollers 66 and thence to the retort 1. The shaft 10 of the stirring mechanism is provided with an extension 101 for driving both shaft 10 and extension 101.

The carbonizing unit consisting of fire box 49, retort 1 and associated mechanism, is mounted on a rigid frame 76, one end of said frame having hinges 102 and 103 connected between the frame and a suitable abutment 76', the other end of the frame being supportedy by adjustable jack-screws 104. By varying the angle or pitch of the retort with respect to the horizontal, the -rate of flow of material to be carbonized therethrough is controlled.

The gas take-off 26 from the dust box 27 is concentric with thel hinges 102 and 103. The take-olf conduit 52 has a sliding fit with the nipple 105 secured to the dust box. This, in combination with the flexible conduit 57, makes it possible to adjust the angle of the retort with respect to the horizontal without disturbing the condenser and gas feed systems. The exhaust gases from the heat exchanger may be used to pre-heat the material to be carbonized before it is introduced into the hopper 7.

A detail of the bearings for the stirring mechanism is shown in Fig. 7. The eccentric collar 13 is carried by the casting 2 in a web 106 of a removable plate. The clamps 107 hold the plate in casting 2. By means of this construction the stirrer can be introduced into the retort,V or. removed therefrom without. removing easting 2., Since the plate. is larger than the stirrer. assembly, eeeentrie provides means ,for adjusting the Contacty of. blades 9 with respect.l to the. interior Wall of the retort. A similar mechanism is provided at. the other end of the retort for supporting; .shaft 10.. These adjustments make: possible. a varying degree of pressure between the blades of the stirrer and the inner wall -ofthe. retort..

A modified forni ofthe invention is illustrated in Figs. 1:0.v through 14. in. which 10S represents the peuftionV of a retort similar to retort 1 described above. A closure. 1.09 is provided therefor in which a, shaft 11,0 is rotatably supported. This shaft. is providedwith. a plurality of blades 111 suitably securedto the shaft for the purpose of stirring the material to be carbonized. A scraper 112 is also rotatably supported in the closure that consists of a pipe 113 to which a rectangular bar 114 is fastened. The bar 114 serves as a scraper for removing the material which may adhere to the interior wall of the retort, the retort being rotatably supported between two rollers 11S. These rollers are rotatably supported on a lever 116 pivot-ally supported on a base 117. The retort is provided withl an: annular track 118 which is in engagement with the; rollers 115. A segmental gear 119 is secured to the annular track and vertical movement is imposed on the retort by permitting the rollers 11,5 toA be moved toward or away from the retort.. This motion is Controlled by positioning screws 120, there being onescrew for cach of the rollers 115 and the lever 11.6, The screw jack and hinge shown in Fig. l is also used for changing the pitch of the retort. The retort is rotated by a drive motor 121, which motor operates a speed changer 122 that drives a gearA 123 meshing with the segmental gear 119. A second gear 124 is associated with gear 123 and drives the shaft 110 and stirring blades `111 by means, of a suitable power transmitting device 125 eonnectable to a suitable gear (not shown) secured to shaft 11b. Relative axial movement of the retort with respect to rollers 115 is prevented by means of a roller 126. which is rotatably supported on base 117. This gear has a beveled opera img face which cooperates with a .correspondingly shaped Surface on track 118. The r 1,26` and the track 11S are in constant engagement with each other so that relative axial motion is prevented. This structure supports one end of the retort, the opposite end of the retort being rotatably supported by structure the same as that just described. This end of the retort is provided with a closure 127 constructed similar to the casting 3. A tapered feed screw conveyor or twist 123 is rotatably supported in the lower end of the closure for the removal of char discharged from the retort. The depth of the char in the closure is measured by a tester 129. The stirring, mixing and scraping mechanism is also supported in the closure.

Fig. 13 shows a lever 130 secured to the pipe 113 to which an adjustable weight 131 is secured. The distance the weight 131 is located from the pipe 113 determines the friction-between scraper 112 and the interior wall for the purpose of scraping any char that adheres to the interior surface of the retort. i

The ends of the retort are provided with suitable insulation and the retort is surrounded by the refractory material shown in Fig. 2 thereof, the ends having means therein for cooling the bearings by means of water or other cooling medium.

A modied construction is disclosed in Figs. l5 and 16 of the drawings showing a portion of one end of the retort 135 having a closure 136 for the discharge end of the retort. The opposite end of the conveyor has a closure similar to that shown in Figs. 2 or ll. A stirring or agitating mechanism 137 is rotatably mounted in the closure and may be fabricated from angle bars suitably welded together or in any other desirable manner to form a multibladed element. This element is located in the retort so that its axis of rotation is positioned on a radius approximately from the vertical. The blades of this mechanism are given a slight helix lead or twist so that it is not necessary to tilt the retort 135 for causing the material to be passed therethrough. Under some conditions of operation wherein the material being charred is sticky and adheres to the blades of the stirring mechanism it is r0- tated at a high rate of speed so that the material will be dislodged from the mechanism blades by centrifugal action.

.In earboniz-,ing retorts et large capacity,` .sueh as sev-d eral hundred tons per day, the lead applied te agitating mechanism ebviates the tilting of the longitudinal axis, of the retort as described above..` The rate at which the mechanism is, rotated and the degree of lead of the helix or twist applied to the blades thereof regulatesl the rate at which material is fed through the retort.

rlfhe scraping mechanism 138 for removing char and other adhering materials is rotatably mounted in the closures for the retort.. This mechanism comprises a tube or rod 139 rotatably supported in the closures, A plurality of individual Scrapers 140 is distributed along the length of the tube or rod 139. These Scrapers are shapedsimilar to. plow shares so that they will move the `material removed from the retort wall toward the discharge end thereof. Each scraper 140 issecured to tube or rod 139 by means of a flexible rod or bar 141 extending throughsaid tube and secured to rings 142 loosely supported on said tube or rod 139 there being t a Welded connection between the scraper 140 and the rings. The flexible rods and rings move and hold the Scrapers in Contact with the interior wall of the retort after the rod or tube 139 is suitably rotationally adjusted. The particular construction compensates for irregularities in the retort surface so that the scrapers will always engage the wall of the retort. Under some conditions of operation the scraper 13S may be omitted and. reliance placed .solely on the agitator this being done where the material becomes plastic and sticky. When the material being carbonized is not inclined towards st ickiness then the scraping mechanism alone is used. In the former construction the vrate of rotation of the retort and the shape of the Scrapers determines the rate at which material passes through the retort, and if necessary the retort mayv be tilted to facilitate material movement therethrough. When only the scraper is used the retort is rotated at a rate ysuch that the material being carbonized will be maintained against the inner wall of the retort.

The closure for the discharge end of the retort shown in Figs. 15 and 16 has a partition 143 therein that extends downwardly substantially to a line drawn through a plane passing through the axis of conveyor screws and twists 144 and 145 rotatably mounted in the 01o-, sure. This partition divides the space in closure 136 into chambers 146 and 1,47. Char discharged from the retort falls into chamber 146 and some is worked by the conveyors into the chamber 147. Gas passes through the char about each conveyor and in the chamber where it is filtered before passing through outlet 148 into duct or tube 52 for further filtering and treatment as described above in connection with Figs. l, 2 and 6. Suitable means are provided for rotating the agitating or stirring mechanism and the two conveyors, such as the devices shown in Figs. 1 through 5 as well as insulating the closures against heat loss.

What we claim is:

l. A carbonizing machine comprising a heat insulated housing, a tubular retort rotatably mounted in said housing, means for introducing material to be carbonized into said retort, means within the retort for rapidly agitating said material, means for heating the interior of said housing and the retort therein, means associated with said agitating means for heating it to a temperature greater than that of the retort for preventing formation of deposits thereon; and scraping means in said retort separate from the agitating means for scraping char from the inner surface thereof.

2. A carbonizing machine comprising a heat insulated housing, a retort rotatably mounted in said housing, means for introducing material to be carbonized into said retort, means for heating said retort, an agitator within the retort, a housing having a chamber therein at the discharge end of said retort into which char is introduced, a lead screw for removing char from said chamber, means for cooling said char by spraying water thereon and forming steam; and means causing at least a portion of the steam to ow through the char in the direction opposite to the direction of movement thereof caused by the lead screw, for removing gases from the char.

3. A carbonizing machine comprising a heat insulated housing, a retort tube rotatably mounted in said housing, means for introducing material to be carbonized into said retort tube, means for rapidly stirring the material in said tube, means for heating said retort tube, a heat exchanger, means for conducting heat from said housing to said heat exchanger, a housing having a chamber therein at the discharge end of said retort tube for receiving char, a lead screw tube secured to said housing, a lead screw in said tube, a gas take-E connected to said lead screw tube, a fan for drawing gas from said retort tube through the char in said chamber and tube, means for applying water to said char for cooling same and forming steam, means for heating at least a portion of the steam in said heat eX- changer; and means for introducing the heated steam into said retort.

4. A carbonizing machine comprising a retort, a pair of track members circumscribing said retort, one of said tracks having a ange thereon, gear segments secured to said flange for forming a gear, means in engagement with each track supporting the retort for rotation, a gear for meshing with the gear segments on said one track, a multi-bladed stirring mechanism in said retort, drive means connected to said gear segments and said stirring mechanism for rotating said re tort and stirring mechanism in opposite directions; and scraper mechanism rockably supported in said retort, including means for mounting the mechanism in engagement with the interior surface of said'retort.

5. A carbonizing machine comprising a retort, an annular track mounted near each end of said retort, one of said tracks having gear segments secured thereto, rollers in engagement with each of said tracks, means for adjusting the rollers toward and away from said retort for adjusting the position thereof, a gear in engagement with the gear segments on said one track, a multi-bladed stirring mechanism rotatably mounted in said retort, drive means connected to said gear segments and stirring mechanism for driving same in opposite directions; and means for scraping material from the interior surface of said retort which includes an angle bar rotatably supported in said retort and means for engaging one edge thereof with the interior surface of the retort.

6. A carbonizing machine, comprising a heat insulated housing; a retort tube rotatably mounted in the housing and having an inlet and an outlet; means for introducing material to be carbonized into the inlet; a chamber adjacent the outlet for receiving the char; a

tubular member having one end thereof in communication with said chamber; a conveyor in the tubular member for moving the char away from said chamber toward the other end of the tubular member; a water spray adjacent said other end of the tubular member for cooling the char and producing steam in the tubular member; passage means connected to the tubular member intermediate the ends thereof; and vacuum producing means associated with the passage means for causing the steam to be drawn through the char in the direction opposite to the movement thereof through the tubular member and for causing the gas within the retort tube to be drawn through the char in the chamber.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 577,359 Cousins Feb. 16, 1897 980,640 Hughes Ian. 3, 1911 1,413,802 Smith et al. Apr. 25, 1922 1,458,410 Hiller June 12, 1923 1,534,737 Reed Apr. 21, 1925 1,538,265 Arnold May 19, 1925 1,538,796 Gorden May 19, 1925 1,561,735 Lucas Nov. 17, 1925 1,698,349 Puening Jan. 8, 1929 1,708,740 Rohmer Apr. 9, 1929 1,735,394 Hiller Nov. 12, 1929 1,735,397 Hiller Nov. 17, 1929 1,742,273 Nilson Jan. 7, 1930 1,830,921 Michelman Nov. 10, 1931 1,859,381 Condit et al. May 24, 1932 1,884,379 Tenney Oct. 25, 1932 1,921,993 McQuade Aug. 8, 1933 1,945,530 Karrick Feb. 6, 1934 1,972,929 Fisher Sept. 11, 1934 2,009,122 Reed et al. July 23, 1935 2,078,333 Lloyd et al. Apr. 27, 1937 2,177,665 Loughrey Oct. 31, 1939 2,158,689 Buchanan May 16, 1939 2,366,057 Russell Dec. 26, 1944 2,406,509 Pilo Aug. 27, 1946 2,456,796 Schutte Dec. 21, 1948 2,595,338 Creelman May 6, 1952 

1. A CARBONIZING MACHINE COMPRISING A HEAT INSULATED HOUSING, A TUBULAR RETORT ROTATABLY MOUNTED IN SAID HOUSING, MEANS FOR INTRODUCING MATERIAL TO BE CARBONZIED INTO SAID RETORT, MEANS WITHIN THE RETORT FOR RAPIDLY AGITATING SAID MATERIAL, MEANS FOR HEATING THE INTERIOR OF SAID HOUSING AND THE RETORT THEREIN, MEANS ASSOCIATED WITH SAID AGITATING MEANS FOR HEATING IT TO A TEMPERATURE GREATER THAN THAT OF THE RETORT FOR PREVENTING FORMATION OF DEPOSITS THEREON; AND SCRAPING MEANS IN SAID RETORT SEPARATE FROM THE AGITATING MEANS FOR SCRAPING CHAR FROM THE INNER SURFACE THEREOF. 